New approach produces 20 percent survival rate in rat model where few typically live
Biomedical engineers at Duke University have recruited an unlikely ally in the fight against the deadliest form of brain cancer—a strain of salmonella that usually causes food poisoning.
Clinicians sorely need new treatment approaches for glioblastoma, the most aggressive form of brain cancer. The blood-brain barrier—a protective sheath separating brain tissue from its blood vessels—makes it difficult to attack the disease with drugs. It’s also difficult to completely remove through surgery, as even tiny remnants inevitably spawn new tumors. Even with the best care currently available, median survival time is a dire 15 months, and only 10 percent of patients survive five years once diagnosed.
The Duke team decided to pursue an aggressive treatment option to match its opponent, turning to the bacterium Salmonella typhimurium. With a few genetic tweaks, the engineers turned the bacterium into a cancer-seeking missile that produces self-destruct orders deep within tumors. Tests in rat models with extreme cases of the disease showed a remarkable 20 percent survival rate over 100 days—roughly equivalent to 10 human years—with the tumors going into complete remission.
The results appeared online on December 21, 2016, in the journal Molecular Therapy – Oncolytics.
“Since glioblastoma is so aggressive and difficult to treat, any change in the median survival rate is a big deal,” said Johnathan Lyon, a PhD student working with Ravi Bellamkonda, Vinik Dean of Duke’s Pratt School of Engineering, whose laboratory is currently transitioning to Duke from Georgia Tech, where much of the work was completed. “And since few survive a glioblastoma diagnosis indefinitely, a 20 percent effective cure rate is phenomenal and very encouraging.”
Previous studies have shown, quite accidentally, that the presence of bacteria can cause the immune system to recognize and begin attacking tumors. However, follow-up clinical trials with genetically detoxified strains of S. typhimurium have since proven ineffective by themselves.
To use these common intestinal bacteria as tumor-seeking missiles, Lyon and Bellamkonda, working with lead co-author Nalini Mehta, selected a detoxified strain of S. typhimurium that was also deficient in a crucial enzyme called purine, forcing the bacteria to seek supplies elsewhere.
Tumors just so happen to be an excellent source of purine, causing the bacteria to flock to them in droves.
Ravi Bellamkonda, Vinik Dean of the Pratt School of Engineering at Duke University
Then, the Duke engineers made a series of genetic tweaks so that the bacteria would produce two compounds called Azurin and p53 that instruct cells to commit suicide—but only in the presence of low levels of oxygen. And since cancerous cells are multiplying so energetically, the environment around and within tumors has unusually low oxygen.
“A major challenge in treating gliomas is that the tumor is dispersed with no clear edge, making them difficult to completely surgically remove. So designing bacteria to actively move and seek out these distributed tumors, and express their anti-tumor proteins only in hypoxic, purine rich tumor regions is exciting,” said Ravi Bellamkonda, Vinik Dean of Duke’s Pratt School of Engineering and corresponding author of the paper. “And because their natural toxicity has been deactivated, they don’t cause an immunological response. At the doses we used in the experiments, they were naturally cleared once they’d killed the tumors, effectively destroying their own food source.”
The researchers tested the modified bacteria by injecting them directly into the rats’ brains. While this may sound like an extreme delivery option, the first course of action usually performed with glioblastoma is to surgically remove the primary tumor, if possible, leaving the opportunity to directly deliver therapeutics.
The treatment worked in 20 percent of the rats, causing complete tumor regression and extending their lives by 100 days, which translates to roughly 10 human years.
In the 80 percent that did not survive, however, the treatment didn’t change the length of time the rats survived. After testing for common signs of resistance to the anti-tumor compounds and finding none, the researchers concluded the ineffectiveness was likely due to inconsistencies in the bacteria’s penetration, or to the aggressive tumor growth outpacing the bacteria. But every rat showed initial signs of improvement after treatment.
“It might just be a case of needing to monitor the treatment’s progression and provide more doses at crucial points in the cancer’s development,” said Lyon. “However, this was our first attempt at designing such a therapy, and there is some nuance to the specific model we used, thus more experiments are needed to know for sure.”
The researchers now plan to program their bacteria to produce different drugs that cause stronger reactions in the tumors. These will be more difficult to implement, however, as other drugs are not as specific to tumor cells as those used in this study, making potential side effects more of a concern.
Learn more: Tumor-Seeking Salmonella Treats Brain Tumors
Founded by Methodists and Quakers in the present-day town of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco and electric power industrialist James B. Duke established The Duke Endowment, at which time the institution changed its name to honor his deceased father, Washington Duke.
The university has “historical, formal, on-going, and symbolic ties” with the United Methodist Church, but is a nonsectarian and independent institution. Duke’s research expenditures in the 2010 fiscal year topped $983 million, the fifth largest figure in the nation. Competing in the Atlantic Coast Conference, Duke’s athletic teams—known as the Blue Devils—have captured 13 team national championships, including four by its high profile men’s basketball team.
The university’s campus spans over 8,600 acres (35 km2) on three contiguous campuses in Durham as well as a marine lab in Beaufort. Duke’s main campus—designed largely by African American architect Julian Abele—incorporates Gothic architecture with the 210-foot (64 m) Duke Chapel at the campus’ center and highest point of elevation. The forest environs surrounding parts of the campus belie the University’s proximity to downtown Durham. Construction projects have updated both the freshmen-populated Georgian-style East Campus and the main Gothic-style West Campus, as well as the adjacent Medical Center over the past five years.
Duke University research articles from Innovation Toronto
- Study Points to Fast-Acting Drug for OCD – July 23, 2016
- Bouncing droplets remove contaminants and self-clean without being superhydrophobic – July 6, 2016
- Robotic motion planning in real-time – June 22, 2016
- Bioengineered Blood Vessel Appears Safe for Dialysis Patients and Becomes Human Tissue – May 16, 2016
- Uncovering Genetic Elements That Drive Limb and Tissue Regeneration – April 7, 2016
- New class of molecular ‘lightbulbs’ illuminate MRI bioimaging in real time – March 27, 2016
- Rapidly Building Arteries that Produce Biochemical Signals – March 1, 2016
- Traveling Salesman Uncorks Synthetic Biology Bottleneck – January 6, 2016
- Using — And Sharing — New Technologies Is Key For Conservation – October 7, 2015
- Engineers Unlock Remarkable 3D Vision from Ordinary Digital Camera Technology – September 18, 2015
- Stem Cells Provide Lasting Pain Relief in Mice – July 15, 2015
- Finding New Life for First-Line Antibiotics – April 26, 2015
- Crowdsourcing with Mobile Apps Brings ‘Big Data’ To Psychological Research – December 23, 2014
- Revving up fluorescence for superfast LEDs & quantum cryptography – October 19, 2014
- The Skin Cancer Selfie – October 8, 2014
- Extinctions during human era worse than thought – September 6, 2014
- Water ‘Thermostat’ Could Help Engineer Drought-Resistant Crops – August 31, 2014
- World Cup to Debut Mind-Controlled Robotic Suit – June 10, 2014
- The Duke University breakthrough that could keep your cancer in remission forever – May 18, 2014
- Neural Networks Imitate Intelligence of Biological Brains – May 17, 2014
- Self-Healing Engineered Muscle Grown in the Laboratory
- Catheter Innovation Destroys Dangerous Biofilms
- ‘Superlens’ Extends Range of Wireless Power Transfer
- Supercomputers Join Search for ‘Cheapium’
- Surgeons at Duke University Hospital Implant Bioengineered Vein
- Duke University researchers create polymer coating to keep bacteria, barnacles at bay
- Duke Engineers Build Living Patch for Damaged Hearts
- Duke researchers engineer cartilage from pluripotent stem cells
- Copper Promises Cheaper, Sturdier Fuel Cells
- Wireless Device Converts “Lost” Energy into Electric Power
- Shifting employee bonuses from self to others increases satisfaction and productivity at work
- Scientists Demonstrate New Method for Harvesting Energy from Light
- Researcher controls colleague’s motions in 1st human brain-to-brain interface
- Far From Being Harmless, the Effects of Bullying Last Long Into Adulthood
- First-Ever Therapeutic Offers Hope for Improving Blood Transfusions
- Light and nanoprobes detect early signs of infection
- Genetic editing shows promise in Duchenne muscular dystrophy
- New Method for Producing Clean Hydrogen
- Do-It-Yourself Invisibility with 3-D Printing
- Medical Equipment Donated to Developing Nations Usually Ends Up on the Junk Heap
- Brain scans might predict future criminal behavior
- Brain-to-brain interface allows transmission of tactile and motor information between rats
- Scrap “unwinnable” drugs war and divert funds into curbing global antibiotic misuse
- Brain prostheses create a sense of touch
- Novel Materials Shake Ship Scum
- Slow-release jelly delivers drugs better
- Novel sensor provides bigger picture
- Scientists Develop Device for Image Compression
- Sprinkled Nanocubes Could Hold Light Tight for Efficient Solar Panels
- Hope on the Horizon for Asthma Sufferers
- Coming Soon: Artificial Limbs Controlled by Thoughts
- Megapixel Camera? Try Gigapixel
- Scar Tissue Turned Into Heart Muscle Without Using Stem Cells
- Large-Scale Analysis Finds Majority of Clinical Trials Don’t Provide Meaningful Evidence
- A New Crop of Digital Science Books Will Change the Way Students Learn
- Changing the Texture of Plastic Instantly
- Exotic Material Boosts Electromagnetism Safely
- Energy Harvesting: Wringing More Energy out of Everyday Motions
- With Prevalence of Nanomaterials Rising, Panel Urges Review of Risks
- Vaccines to Boost Immunity Where It Counts, Not Just Near Shot Site
- Jumping droplets could offer more efficient thermal management
- Digital Merit Badges For Job Hunters
- Monkeys’ brain waves offer paraplegics hope
- Harnessing the Power of Positive Thoughts and Emotions to Treat Depression
- Hybrid Solar System Makes Rooftop Hydrogen
- Manipulating Light at Will
- Restoring Happiness in People With Depression
- Automatic photo tagging with TagSense smartphone app
- New Wifi Tech Could Double Your Phone’s Battery Life
- Food Allergy Therapies Move Closer to Approval
- Metamaterials could significantly boost wireless power transmission
- Skin cancer-detecting laser tool developed
- New Antibacterial Chemical Compound Discovered
- Color-changing plants detect pollutants and explosives
- Shooting for the Moon: How Universities Can Turn Innovation into Companies
- Free the H-1Bs, Free the Economy
- Renewable Energies Will Benefit US Workers’ Health, Expert Predicts
- When the Software Is the Sportswriter
- Scientists Isolate a Gene That Boosts Plant Root Growth
- Researchers discover way to turn off severe allergic reaction to food in mice
- Next-gen robotic surgeons could eliminate need for doctors in simple surgeries
- Bye-Bye Batteries: Radio Waves as a Low-Power Source
- Energy-efficiency measures could save consumers $41 billion
- New visa proposal to help create the next big thing
- Harvesting Energy From Nature’s Motions
- Weary of Looking for Work, Some Create Their Own
- Next Generation Cloaking Device Demonstrated
- Telerobotic system designed to treat bladder cancer
- Robotic fish to patrol for pollution in harbours
- How Do We Measure What Really Counts In The Classroom
- In Study, Drug Delays Worsening of Breast Cancer, With Fewer Side Effects
- US-China Deal Intended to Speed Clean Coal Research
- Effortless Sailing With Fluid Flow Cloak
- EnerJ system could cut computer power consumption by up to 90 percent
- Bendable displays and solar cells using cheap copper nanowires
The global spread of green technologies must quicken significantly to avoid future rebounds in greenhouse gas emissions, a new Duke University study shows.
“Based on our calculations, we won’t meet the climate warming goals set by the Paris Agreement unless we speed up the spread of clean technology by a full order of magnitude, or about ten times faster than in the past,” said Gabriele Manoli, a former postdoctoral associate at Duke’s Nicholas School of the Environment, who led the study.
“Radically new strategies to implement technological advances on a global scale and at unprecedented rates are needed if current emissions goals are to be achieved,” Manoli said.
The study used delayed differential equations to calculate the pace at which global per-capita emissions of carbon dioxide have increased since the Second Industrial Revolution — a period of rapid industrialization at the end of the 19th century and start of the 20th. The researchers then compared this pace to the speed of new innovations in low-carbon-emitting technologies.
Using these historical trends coupled with projections of future global population growth, Manoli and his colleagues were able to estimate the likely pace of future emissions increases and also determine the speed at which climate-friendly technological innovation and implementation must occur to hold warming below the Paris Agreement’s 2o C target.
“It’s no longer enough to have emissions-reducing technologies,” he said. “We must scale them up and spread them globally at unprecedented speeds.”
The researchers published their peer-reviewed findings December 29 in the open-access journal Earth’s Future.
The analysis shows that per-capita CO2 emissions have increased about 100 percent every 60 years — typically in big jumps — since the Second Industrial Revolution. This “punctuated growth” has occurred largely because of time lags in the spread of emission-curbing technological advances, which are compounded by the effects of rapid population growth.
“Sometimes these lags are technical in nature, but — as recent history amply demonstrates — they also can be caused by political or economic barriers,” Manoli explained. “Whatever the cause, our quantification of the delays historically associated with such challenges shows that a tenfold acceleration in the spread of green technologies is now necessary to cause some delay in the Doomsday Clock.”
By suspending tiny metal nanoparticles in liquids, paper-based printable electronics scientists are brewing up conductive ink-jet printer “inks” to print inexpensive, customizable circuit patterns on just about any surface.
Printed electronics, which are already being used on a wide scale in devices such as the anti-theft radio frequency identification (RFID) tags you might find on the back of new DVDs, currently have one major drawback: for the circuits to work, they first have to be heated to melt all the nanoparticles together into a single conductive wire, making it impossible to print circuits on inexpensive plastics or paper.
A new study by Duke researchers shows that tweaking the shape of the nanoparticles in the ink might just eliminate the need for heat.
By comparing the conductivity of films made from different shapes of silver nanostructures, the researchers found that electrons zip through films made of silver nanowires much easier than films made from other shapes, like nanospheres or microflakes. In fact, electrons flowed so easily through the nanowire films that they could function in printed circuits without the need to melt them all together.
“The nanowires had a 4,000 times higher conductivity than the more commonly used silver nanoparticles that you would find in printed antennas for RFID tags,” said Benjamin Wiley, assistant professor of chemistry at Duke. “So if you use nanowires, then you don’t have to heat the printed circuits up to such high temperature and you can use cheaper plastics or paper.”
“There is really nothing else I can think of besides these silver nanowires that you can just print and it’s simply conductive, without any post-processing,” Wiley added.
These types of printed electronics could have applications far beyond smart packaging; researchers envision using the technology to make solar cells, printed displays, LEDS, touchscreens, amplifiers, batteries and even some implantable bio-electronic devices. The results appeared online Dec. 16 in ACS Applied Materials and Interfaces.
Silver has become a go-to material for making printed electronics, Wiley said, and a number of studies have recently appeared measuring the conductivity of films with different shapes of silver nanostructures. However, experimental variations make direct comparisons between the shapes difficult, and few reports have linked the conductivity of the films to the total mass of silver used, an important factor when working with a costly material.
“We wanted to eliminate any extra materials from the inks and simply hone in on the amount of silver in the films and the contacts between the nanostructures as the only source of variability,” said Ian Stewart, a recent graduate student in Wiley’s lab and first author on the ACS paper.
Stewart used known recipes to cook up silver nanostructures with different shapes, including nanoparticles, microflakes, and short and long nanowires, and mixed these nanostructures with distilled water to make simple “inks.” He then invented a quick and easy way to make thin films using equipment available in just about any lab — glass slides and double-sided tape.
“We used a hole punch to cut out wells from double-sided tape and stuck these to glass slides,” Stewart said. By adding a precise volume of ink into each tape “well” and then heating the wells — either to relatively low temperature to simply evaporate the water or to higher temperatures to begin melting the structures together — he created a variety of films to test.
The team say they weren’t surprised that the long nanowire films had the highest conductivity. Electrons usually flow easily through individual nanostructures but get stuck when they have to jump from one structure to the next, Wiley explained, and long nanowires greatly reduce the number of times the electrons have to make this “jump”.
But they were surprised at just how drastic the change was. “The resistivity of the long silver nanowire films is several orders of magnitude lower than silver nanoparticles and only 10 times greater than pure silver,” Stewart said.
The team is now experimenting with using aerosol jets to print silver nanowire inks in usable circuits. Wiley says they also want to explore whether silver-coated copper nanowires, which are significantly cheaper to produce than pure silver nanowires, will give the same effect.
New technology allows multispectral reactions on a single chip
Duke University researchers believe they have overcome a longstanding hurdle to producing cheaper, more robust ways to print and image across a range of colors extending into the infrared.
As any mantis shrimp will tell you, there are a wide range of “colors” along the electromagnetic spectrum that humans cannot see but which provide a wealth of information. Sensors that extend into the infrared can, for example, identify thousands of plants and minerals, diagnose cancerous melanomas and predict weather patterns, simply by the spectrum of light they reflect.
Current imaging technologies that can detect infrared wavelengths are expensive and bulky, requiring numerous filters or complex assemblies in front of an infrared photodetector. The need for mechanical movement in such devices reduces their expected lifetime and can be a liability in harsh conditions, such as those experienced by satellites.
In a new paper, a team of Duke engineers reveals a manufacturing technique that promises to bring a simplified form of multispectral imaging into daily use. Because the process uses existing materials and fabrication techniques that are inexpensive and easily scalable, it could revolutionize any industry where multispectral imaging or printing is used.
The results appear online December 14 in the journal Advanced Materials.
“It’s challenging to create sensors that can detect both the visible spectrum and the infrared,” said Maiken Mikkelsen, the Nortel Networks Assistant Professor of Electrical and Computer Engineering and Physics at Duke.
“Traditionally you need different materials that absorb different wavelengths, and that gets very expensive,” Mikkelsen said. “But with our technology, the detectors’ responses are based on structural properties that we design rather than a material’s natural properties. What’s really exciting is that we can pair this with a photodetector scheme to combine imaging in both the visible spectrum and the infrared on a single chip.”
The new technology relies on plasmonics — the use of nanoscale physical phenomena to trap certain frequencies of light.
Engineers fashion silver cubes just 100 nanometers wide and place them only a few nanometers above a thin gold foil. When incoming light strikes the surface of a nanocube, it excites the silver’s electrons, trapping the light’s energy — but only at a certain frequency.
The size of the silver nanocubes and their distance from the base layer of gold determines that frequency, while controlling the spacing between the nanoparticles allows tuning the strength of the absorption. By precisely tailoring these spacings, researchers can make the system respond to any specific color they want, all the way from visible wavelengths out to the infrared.
The challenge facing the engineers is how to build a useful device that could be scalable and inexpensive enough to use in the real world. For that, Mikkelsen turned to her research team, including graduate student Jon Stewart.
“Similar types of materials have been demonstrated before, but they’ve all used expensive techniques that have kept the technology from transitioning to the market,” said Stewart. “We’ve come up with a fabrication scheme that is scalable, doesn’t need a clean room and avoids using million-dollar machines, all while achieving higher frequency sensitivities. It has allowed us to do things in the field that haven’t been done before.”
To build a detector, Mikkelsen and Stewart used a process of light etching and adhesives to pattern the nanocubes into pixels containing different sizes of silver nanocubes, and thus each sensitive to a specific wavelength of light. When incoming light strikes the array, each area responds differently depending on the wavelength of light it is sensitive to. By teasing out how each part of the array responds, a computer can reconstruct what color the original light was.
The technique can be used for printing as well, the team showed. Instead of creating pixels with six sections tuned to respond to specific colors, they created pixels with three bars that reflect three colors: blue, green and red. By controlling the relative lengths of each bar, they can dictate what combination of colors the pixel reflects. It’s a novel take on the classic RGB scheme first used in photography in 1861.
But unlike most other applications, the plasmonic color scheme promises to never fade over time and can be reliably reproduced with tight accuracy time and again. It also allows its adopters to create color schemes in the infrared.
“Again, the exciting part is being able to print in both visible and infrared on the same substrate,” said Mikkelsen. “You could imagine printing an image with a hidden portion in the infrared, or even covering an entire object to tailor its spectral response.”
New technology shapes sound waves for applications from speakers to ultrasound imaging
Research Triangle engineers have developed a simple, energy-efficient way to create three-dimensional acoustic holograms. The technique could revolutionize applications ranging from home stereo systems to medical ultrasound devices.
Most everyone is familiar with the concept of visual holograms, which manipulate light to make it appear as though a 3-D object is sitting in empty space. These optical tricks work by shaping the electromagnetic field so that it mimics light bouncing off an actual object.
Sound also travels in waves. But rather than electromagnetic energy traveling through space, sound propagates as pressure waves that momentarily compress the molecules they are traveling through. And just like visible light, these waves can be manipulated into three-dimensional patterns.
A close up look at the metamaterial device that can create acoustic holograms. Each grid or block contains a spiral of one of 12 various densities, each of which slows sound waves by a specific amount.
“We show the exact same control over a sound wave as people have previously achieved with light waves,” said Steve Cummer, professor of electrical and computer engineering at Duke University. “It’s like an acoustic virtual reality display. It gives you a more realistic sense of the spatial pattern of the sound field.”
In a paper published Oct. 14 in Nature Scientific Reports, researchers at Duke and North Carolina State University show that they can create any three-dimensional pattern they want with sound waves. The achievement is made possible by metamaterials—synthetic materials composed of many individual, engineered cells that together produce unnatural properties.
A computer rendering if the 12 different kinds of spirals contained in the metamaterial blocks, each of which slows sound waves by a specific amount. Organizing the various spirals in an array can bend the shape of in incoming wave of sound.
In this case, the metamaterials resemble a wall of Legos. Each individual block is made of plastic by a 3-D printer and contains a spiral within. The tightness of the spiral affects the way sound travels through it—the tighter the coil, the slower sound waves travel through it.
While the individual blocks can’t influence the sound wave’s direction, the entire device effectively can. For example, if one side of the sound wave is slowed down but not the other, the resulting wave fronts will be redirected so that the sound is bent toward the slow side.
“Anybody can tell the difference between a single stereo speaker and a live string quartet playing music behind them,” explained Yangbo “Abel” Xie, a doctoral student in Cummer’s laboratory. “Part of the reason why is that the sound waves carry spatial information as well as notes and volume.”
By calculating how 12 different types of acoustic metamaterial building blocks will affect the sound wave, researchers can arrange them in a wall to form any wave pattern on the other side that they want. With enough care, the sound waves can produce a specific hologram at a specific distance away.
“It’s basically like putting a mask in front of a speaker,” said Cummer. “It makes it seem like the sound is coming from a more complicated source than it is.”
A computer rendering of a sound wave that traveled through an array of acoustic metamaterial and was shaped into a pattern like the letter A one foot past the array. This pattern could not be seen, only heard.
Cummer and Xie, in collaboration with Yun Jing, assistant professor of mechanical and aerospace engineering at NC State, and Tarry Shen, a doctoral student in Jing’s lab, proved their sound mask works in two different ways. In the first test, they assembled a metamaterial wall that manipulated an incoming sound wave into a shape like the letter “A” about a foot away. In a second demonstration, they showed that the technique can focus sound waves into several “hot spots”—or loud spots—of sound, also a foot from the device.
There are existing technologies that can also produce this effect. Modern ultrasound imaging devices, for example, use phased arrays with many individual transducers that can each produce precisely controlled sound waves. But this approach has its drawbacks.
“If you’ve ever had an ultrasound done, you know there’s a small wand attached to a much bigger machine a few feet away,” said Cummer. “Not only can this setup be cumbersome, it consumes an enormous amount of power. Our approach can help produce the same effect in a cheaper, smaller system.”
For the metamaterial device to work in such applications, however, each cell must be smaller than the waves it is manipulating. And for ultrasound technologies that operate in the megahertz range, this means the individual cells would have to be 100 times smaller than in the current demonstration blocks.
Computer simulations and experimental results of the effectiveness of the metamaterial acoustic hologram device producing the letter A. The sound wave was manipulated to create the letter A 300mm past the metamaterial device. Test results show a result close to calculations.
Cummer and Xie are looking for industry partners to show that this sort of fabrication would be possible. They are also shopping the idea around to industries that work in the kilohertz range, such as aerial sensing and imaging technologies. And of course, they’re speaking with sound companies to make a single speaker sound more like a live orchestra.
Computer simulations and experimental results of the effectiveness of the metamaterial acoustic hologram device producing several focal points or “hot spots.” The sound wave was manipulated to create the hot spots 300mm past the metamaterial device. Test results show a result close to calculations.
“We’re currently in the exploration phase, trying to determine where this technology would be useful,” said Xie. “Any scenario where your goal is to control sound, this idea could be deployed. And it could be deployed to make something totally new, or to make something that already exists better, simpler or cheaper.”
‘Love hormone’ gives greater sense of spirituality than a placebo
Oxytocin has been dubbed the “love hormone” for its role promoting social bonding, altruism and more. Now new research from Duke University suggests the hormone may also support spirituality.
In the study, men reported a greater sense of spirituality shortly after taking oxytocin and a week later. Participants who took oxytocin also experienced more positive emotions during meditation, said lead author Patty Van Cappellen, a social psychologist at Duke.
“Spirituality and meditation have each been linked to health and well-being in previous research,” Van Cappellen said. “We were interested in understanding biological factors that may enhance those spiritual experiences.
“Oxytocin appears to be part of the way our bodies support spiritual beliefs.”
Study participants were all male, and the findings apply only to men, said Van Cappellen, associate director of the Interdisciplinary and Behavioral Research Center at Duke’s Social Science Research Institute. In general, oxytocin operates somewhat differently in men and women, Van Cappellen added. Oxytocin’s effects on women’s spirituality still needs to be investigated.
The results appears online in the journal Social Cognitive and Affective Neuroscience.
Oxytocin occurs naturally in the body. Produced by the hypothalamus, it acts as a hormone and as a neurotransmitter, affecting many regions of the brain. It is stimulated during sex, childbirth and breastfeeding. Recent research has highlighted oxytocin’s possible role in promoting empathy, trust, social bonding and altruism.
To test how oxytocin might influence spirituality, researchers administered the hormone to one group and a placebo to another. Those who received oxytocin were more likely to say afterwards that spirituality was important in their lives and that life has meaning and purpose. This was true after taking into account whether the participant reported belonging to an organized religion or not.
Participants who received oxytocin were also more inclined to view themselves as interconnected with other people and living things, giving higher ratings to statements such as “All life is interconnected” and “There is a higher plane of consciousness or spirituality that binds all people.”
Study subjects also participated in a guided meditation. Those who received oxytocin reported experiencing more positive emotions during meditation, including awe, gratitude, hope, inspiration, interest, love and serenity.
Oxytocin did not affect all participants equally, though. Its effect on spirituality was stronger among people with a particular variant of the CD38 gene, a gene that regulates the release of oxytocin from hypothalamic neurons in the brain.
Van Cappellen cautioned that the findings should not be over-generalized. First of all, there are many definitions of spirituality, she noted.
“Spirituality is complex and affected by many factors,” Van Cappellen said. “However, oxytocin does seem to affect how we perceive the world and what we believe.”
Learn more: OXYTOCIN ENHANCES SPIRITUALITY, NEW STUDY SAYS
Duke engineers use CRISPR to generate neuronal cells from connective tissue
Researchers have used CRISPR—a revolutionary new genetic engineering technique—to convert cells isolated from mouse connective tissue directly into neuronal cells.
In 2006, Shinya Yamanaka, a professor at the Institute for Frontier Medical Sciences at Kyoto University at the time, discovered how to revert adult connective tissue cells, called fibroblasts, back into immature stem cells that could differentiate into any cell type. These so-called induced pluripotent stem cells won Yamanaka the Nobel Prize in medicine just six years later for their promise in research and medicine.
Since then, researchers have discovered other ways to convert cells between different types. This is mostly done by introducing many extra copies of “master switch” genes that produce proteins that turn on entire genetic networks responsible for producing a particular cell type.
Now, researchers at Duke University have developed a strategy that avoids the need for the extra gene copies. Instead, a modification of the CRISPR genetic engineering technique is used to directly turn on the natural copies already present in the genome.
These early results indicate that the newly converted neuronal cells show a more complete and persistent conversion than the method where new genes are permanently added to the genome. These cells could be used for modeling neurological disorders, discovering new therapeutics, developing personalized medicines and, perhaps in the future, implementing cell therapy.
The study was published on August 11, 2016, in the journal Cell Stem Cell.
“This technique has many applications for science and medicine. For example, we might have a general idea of how most people’s neurons will respond to a drug, but we don’t know how your particular neurons with your particular genetics will respond,” said Charles Gersbach, the Rooney Family Associate Professor of Biomedical Engineering and director for the Center for Biomolecular and Tissue Engineering at Duke. “Taking biopsies of your brain to test your neurons is not an option. But if we could take a skin cell from your arm, turn it into a neuron, and then treat it with various drug combinations, we could determine an optimal personalized therapy.”
“The challenge is efficiently generating neurons that are stable and have a genetic programming that looks like your real neurons,” says Joshua Black, the graduate student in Gersbach’s lab who led the work. “That has been a major obstacle in this area.”
In the 1950s, Professor Conrad Waddington, a British developmental biologist who laid the foundations for developmental biology, suggested that immature stem cells differentiating into specific types of adult cells can be thought of as rolling down the side of a ridged mountain into one of many valleys. With each path a cell takes down a particular slope, its options for its final destination become more limited.
If you want to change that destination, one option is to push the cell vertically back up the mountain—that’s the idea behind reprogramming cells to be induced pluripotent stem cells. Another option is to push it horizontally up and over a hill and directly into another valley.
“If you have the ability to specifically turn on all the neuron genes, maybe you don’t have to go back up the hill,” said Gersbach.
Previous methods have accomplished this by introducing viruses that inject extra copies of genes to produce a large number of proteins called master transcription factors. Unique to each cell type, these proteins bind to thousands of places in the genome, turning on that cell type’s particular gene network. This method, however, has some drawbacks.
“Rather than using a virus to permanently introduce new copies of existing genes, it would be desirable to provide a temporary signal that changes the cell type in a stable way,” said Black. “However, doing so in an efficient manner might require making very specific changes to the genetic program of the cell.”
In the new study, Black, Gersbach, and colleagues used CRISPR to precisely activate the three genes that naturally produce the master transcription factors that control the neuronal gene network, rather than having a virus introduce extra copies of those genes.
CRISPR is a modified version of a bacterial defense system that targets and slices apart the DNA of familiar invading viruses. In this case, however, the system has been tweaked so that no slicing is involved. Instead, the machinery that identifies specific stretches of DNA has been left intact, and it has been hitched to a gene activator.
The CRISPR system was administered to mouse fibroblasts in the laboratory. The tests showed that, once activated by CRISPR, the three neuronal master transcription factor genes robustly activated neuronal genes. This caused the fibroblasts to conduct electrical signals—a hallmark of neuronal cells. And even after the CRISPR activators went away, the cells retained their neuronal properties.
“When blasting cells with master transcription factors made by viruses, it’s possible to make cells that behave like neurons,” said Gersbach. “But if they truly have become autonomously functioning neurons, then they shouldn’t require the continuous presence of that external stimulus.”
The experiments showed that the new CRISPR technique produced neuronal cells with an epigenetic program at the target genes matching the neuronal markings naturally found in mouse brain tissue.
“The method that introduces extra genetic copies with the virus produces a lot of the transcription factors, but very little is being made from the native copies of these genes,” explained Black. “In contrast, the CRISPR approach isn’t making as many transcription factors overall, but they’re all being produced from the normal chromosomal position, which is a powerful difference since they are stably activated. We’re flipping the epigenetic switch to convert cell types rather than driving them to do so synthetically.”
The next steps, according to Black, are to extend the method to human cells, raise the efficiency of the technique and try to clear other epigenetic hurdles so that it could be applied to model particular diseases.
“In the future, you can imagine making neurons and implanting them in the brain to treat Parkinson’s disease or other neurodegenerative conditions,” said Gersbach. “But even if we don’t get that far, you can do a lot with these in the lab to help develop better therapies.”
Brain receptor acts as switch for OCD symptoms in mice
A single chemical receptor in the brain is responsible for a range of symptoms in mice that are reminiscent of obsessive-compulsive disorder (OCD), according to a Duke University study that appears online in the journal Biological Psychiatry.
The findings provide a new mechanistic understanding of OCD and other psychiatric disorders and suggest that they are highly amenable to treatment using a class of drugs that has already been investigated in clinical trials.
“These new findings are enormously hopeful for considering how to approach neurodevelopmental diseases and behavioral and thought disorders,” said the study’s senior investigator Nicole Calakos, M.D., Ph.D., an associate professor of neurology and neurobiology at the Duke University Medical Center.
OCD, which affects 3.3 million people in the United States, is an anxiety disorder that is characterized by intrusive, obsessive thoughts and repeated compulsive behaviors that collectively interfere with a person’s ability to function in daily life.
Researchers at Duke University and the University of British Columbia are exploring whether surfaces can shed dirt without being subjected to fragile coatings
Scalpels that never need washing. Airplane wings that de-ice themselves. Windshields that readily repel raindrops. While the appeal of a self-cleaning, hydrophobic surface may be apparent, the extremely fragile nature of the nanostructures that give rise to the water-shedding surfaces greatly limit the durability and use of such objects.
To remedy this, researchers at Duke University in Durham, North Carolina and the University of British Columbia in Vancouver, Canada, are investigating the mechanisms of self-propulsion that occur when two droplets come together, catapulting themselves and any potential contaminants off the surface of interest. They ultimately hope to determine whether superhydrophobicity — a surface that is impossible to wet — is a necessary requirement for self-cleaning surfaces.
“The self-propelled catapulting process is somewhat analogous to pogo jumping,” said Chuan-Hua Chen, an associate professor in the Department of Mechanical Engineering and Materials Science at Duke University. He and his colleagues present their work this week in Applied Physics Letters, from AIP Publishing.
When the droplets coalesce, or come together on a solid particle, they release energy – analogous to the release of biochemical energy of a human body on a pogo stick. The energy is then converted through the interaction between the oscillating liquid drop and the solid particle – analogous to the storage and conversion of energy by the spring mechanism of the pogo stick.
“In both cases, the catapulting is produced by internally generated energy, and the ultimate launching comes from the ground that supports the payload – the solid particle or the pogo stick,” Chen said.
Duke University engineers and computer scientists develop a new computer processor specially designed for robotic motion planning
Once they’ve mastered the skills of toddlerhood, humans are pretty good at what roboticists call “motion planning” — reaching around obstacles to precisely pick up a soda in a crowded fridge, or slipping their hands around a screen to connect an unseen cable.
But for robots with multi-jointed arms, motion planning is a hard problem that requires time-consuming computation. Simply picking an object up in an environment that has not been pre-engineered for the robot may require several seconds of computation.
Duke University researchers have introduced a specially-designed computer processor for motion planning that can plan up to 10,000 times faster than existing approaches while consuming a small fraction of the power. The new processor is fast enough to plan and operate in real time, and power-efficient enough to be used in large-scale manufacturing environments with thousands of robots.
DNA may be the blueprint of life, but it’s also a molecule made from just a few simple chemical building blocks. Among its properties is the ability to conduct an electrical charge, fueling an engineering race to develop novel, low-cost nanoelectronic devices.
Now, a team led by ASU Biodesign Institute researcher Nongjian “N.J.” Tao and Duke theorist David Beratan has been able to understand and manipulate DNA to more finely tune the flow of electricity through it. The key findings, which can make DNA behave in different ways — cajoling electrons to smoothly flow like electricity through a metal wire, or hopping electrons about like the semiconductors materials that power our computers and cellphones — pave the way for an exciting new avenue of research advancements.
The results, published in the online edition of Nature Chemistry, may provide a framework for engineering more stable and efficient DNA nanowires, and for understanding how DNA conductivity might be used to identify gene damage.
Building on a series of recent works, the team has been able to better understand the physical forces behind DNA’s affinity for electrons.
“We’ve been able to show theoretically and experimentally that we can make DNA tunable by changing the sequence of the ‘A, T, C, or G’ chemical bases, by varying its length, by stacking them in different ways and directions, or by bathing it in different watery environments,” said Tao, who directs the Biodesign Center for Biolectronics and Biosensors and is a professor in the Ira A. Fulton Schools of Engineering.